[Pharmacokinetics of SK & F 104864 in experimental animals. II. Tissue distribution].

After intravenous bolus injection of a camptothecin derivative, SK & F 104864 (topotecan), at 20 mg/kg into Sarcoma 180 bearing mice, the tissue concentration of total topotecan (SK & F 104864 plus SK & F 105992) in the mice decreased bi-exponentially, and the beta half-lives in most tissues were longer than those in plasma. The AUCs of total topotecan were extremely large in the kidney, that was followed by the pancreas > intestine > stomach > spleen > liver > thymus > lung > tumor > uterus > plasma. The concentration of total topotecan after 24 hours decreased to less than 2% of the peak level in most tissues except the kidney.